Independent concedes in Qld by-election

The Liberal National Party has snared victory in Queensland's Toowoomba South by-election, maintaining its numbers in the state's tightly balanced parliament.

Independent candidate Di Thorley conceded defeat in the by-election on Tuesday afternoon, a day after the LNP's David Janetzki declared he'd been elected in the seat vacated by now federal MP John McVeigh.

"Although the Electoral Commission Queensland is yet to formally call the election result it appears the LNP have won on preferences. I again thank all the volunteers and people of Toowoomba South that supported me," Ms Thorley posted on Facebook.

Ms Thorley, Toowoomba's former mayor, also hit out at a smear campaign against her after claiming dishonest leaflets about her had been distributed, while push polling had also taken place.

"Unfortunately the unnecessary vitriolic campaign that was run has taken a toll," she wrote.

"In saying this I have not lost my love of the City of Toowoomba or the people in it. I wish the people of Toowoomba South all the best in the next 18 months."

The concession came after Mr Janetzki told supporters he had been elected to keep the LNP's number of seats at 42 in the state's parliament.